I really don't see the need for using (yet another) a plugin for something so trivially simple
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PietApr 15 '11 at 15:06

Plugins are faster, easier to work with, don't require ridiculous hacks, and often well maintained if you pick the right ones. Since Revision Control is maintained by dd32 (a core team member), then you know it will work significantly into the future.
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OttoApr 15 '11 at 18:00

2

In this case, Revision Control provides an easy way to change the number of revisions, automatically will clean up old revisions for you (without running manual SQL queries), lets you delete specific revisions, and allows the number of revisions to be adjusted on a per-post basis. All without editing any files.
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OttoApr 15 '11 at 18:06

I'm not sure of an automatic way but there is always running the MySQL Query DELETE FROM wp_posts WHERE post_type = "revision" (source) I haven't done it but I'm sure it works. I'd look for a plugin by now there has to be something.